Fig. 3: Spectral shape programming.

a, b Logarithmic and linear curves of the fitted hyperbolic secant spectrum with an FWHM of 10.63 nm, with a normalized mean-squared error (NMSE) between the acquired pulse and the standard pulse of 0.0001. c, d Logarithmic and linear curves of the fitted hyperbolic secant spectrum with an FWHM of 17.06 nm, with an NMSE between the acquired pulse and the standard pulse of 0.00024. e–h Triangular-spectrum programming results. e Triangular spectrum. f, g The undispersed waveform and a magnified view. h The NMSE between the acquired pulse and the standard pulse is 0.00127.